OK, so you can't get to that item for now. I suspected that that ice maze was impossible, since I wasn't able to solve it myself, so I'll go change it now.

For attachment 1, that's what I assume you meant as 'entrance to Route 112 in the northern part of the desert'. The reason I cant pass is shown in attachment 2. Also, I dont know if I was supposed to or not, but I did manage to return to Fort Draco as well as go to Sootopolis City. Lastly, what's the deal with the 'sea monster' at the bottom of the waterfall of Ever Grande City?